Preparation for a new green-emitting phosphor for cold cathode fluorescent lamp

A new type of phosphor Ce0.67Tb0.33Mg1−xMnxAl11O19 was obtained by substituting Mn for Mg of Ce0.67Tb0.33MgAl11O19. This new phosphor improved the green ratio dramatically, compared with the conventional phosphor. Besides Tb missions originating from 5D3,4→7Fj=6,5,4,3,2, a broad band at 518 nm was observed and that was the characteristic transition of Mn2+ (4T1(t42ge1g)→6A1(t32ge2g)). It resolved the problem that green ratio of Ce0.67Tb0.33MgAl11O19 was too low for thin-film-transistor liquid-crystal-display backlight. In addition, this paper also studied the influence of Mn2+ content from 0 to 50 at% on luminescence characteristics. The result showed that the brightness did not vary when content was in the range 0–18 at%; however, the green ratio increased from 0.46 to 0.76. A possible structure model was discussed for the possible location of Mn2+ ion in lattice at the end of the paper.